Flame forming burner construction



9 T. s. VOORHEIS 3,409,383

FLAME FORMING BURNER CONSTRUCTION Filed May 9, 1967 INVENTOR- TEMPLE 8.VOORHEIS tmmsama W1 mm/Q A TTO RNEYS United States Patent 3,409,383FLAME FORMING BURNER CONSTRUCTION Temple S. Voorheis, Palo Alto, Calif.,assignor to Coen Company, Burlingame, Calif., a corporation ofCalifornia Filed May 9, 1967, Ser. No. 637,123 2 Claims. (Cl. 431-474)ABSTRACT OF THE DISCLOSURE A combustion chamber wall defining a throatopening that is shaped in accordance with the flame shape desired, whichin turn is dictated by the combustion chamber configuration. A fuelnozzle formed with plural fuel outlet openings so arranged and orientedto cooperate with the asymmetrical burner throat to form anasymmetricallyshaped flame in a combustion chamber.

The present invention provides an improved burner for forming a flamefor firing large boilers in an extremely eflicient manner with a singleburner. A burner according to the invention substantially fills thecombustion chamber of the boiler with flame and the flame is shaped soas to avoid direct impingement onto the interior walls of the combustionchamber. These advantages are achieved without utilizing excessive airsupply and without providing plural openings or fuel nozzles in theboiler furnace wall.

In the foregoing environment the invention provides a burner throatopening that is formed adjacent the lower portion of the boilercombustion chamber wall and midway between the lateral walls of thecombustion chamher. The burner throat terminates at the interior of thecombustion chamber in an opening that is symmetrical relative a verticalaxis and asymmetrical relative a horizontal axis. The amount or degreeof asymmetry is established so that the lower portion of the flame pathcreated by the burner moves adjacent the floor of the combustion chamberand adjacent the opposite wall thereof, whereas the upper portion of theflame path moves upwardly in the furnace and adjacent the wall in whichI the throat opening is formed.

In conjunction with the novel burner throat of the invention, a fuelinjecting nozzle is provided. The nozzle has plural drilled openingsthat are sized and oriented relative the throat to produce the desiredflame shape. "By combining appropriate orientation and size of thenozzle openings with the improved throat configuration, excellentefficiency is achieved because the fuel nozzle openings that directatomized fuel toward the surface of the throat are so proportioned andare formed at such angle that direct impingement on the throat surfaceis avoided along any axis. Thus, buildup of carbon deposit on the throatis eliminated.

An object of the present invention is to provide a single burner forfiring a combustion chamber, which burner provides a flame patternhaving a predetermined shape that substantially fills the combustionchamber without permitting direct flame impingement on the combustionchamber wall opposite the burner throat.

Another object is to provide a burner of the type alluded to above whichis particularly suitable in firing burners having a substantial heightand width to depth ratio.

These and other objects will be more apparent after referring to thefollowing specification and accompanying drawings in which;

In the drawings:

FIGURE 1 is a cross-sectional elevational view of a boiler combustionchamber employing the present inven- 1 tion and taken through the centerof the burner throat;

ill

FIGURE 2 is a cross-sectional plan view taken through the center of theburner throat;

FIGURE 3 is a view of the burner throat as seen from the interior of thecombustion chamber;

FIGURE 4 is an elevational view in cross-section of a fuel nozzle takenat greatly enlarged scale and along line 44 of FIGURE 5;

FIGURE 5 is an end view of the nozzle taken along line 55 of FIGURE 4;and

FIGURE 6 is a horizontal cross-sectional view taken along line 66 ofFIGURE 5.

Referring more particularly to the drawings, reference numeral 12indicates a fragment of the front wall of a boiler combustion chamber,which combustion chamber also has a rear wall 14 and a floor 16. Mountedadjacent or embedded within the walls 12 and 14 are water tubes (notshown), which in accordance with conventional boiler technology,communicate with a header for supplying water to the steam forming watertubes. The boiler wall 12 includes an outer face 18 and an inner face20. A burner throat 22 is formed in wall 12 between the outer and innerfaces.

Throat 22 at the outer face 18 defines a circular orifice indicated at24. The throat, at inner wall face 20, defines an orifice of distortedoval form indicated at 26 in FIG- URE 3, the distortion being a somewhatflattened segment at the bottom (see reference numeral 28 in FIG. 1).Flattened segment 28 functions to avoid impingement of flame directlyonto floor 16. The upper segment of orifice 26 is curved continuouslyupwardly as at 30 to permit the flame pattern to rise rapidly andadjacent to inner surface 20 of front wall 12. As can be seen at FIGURE2, the throat is symmetrical with respect to a horizontal axis and thewall surfaces are flared out widely at 32 for permitting the flame tospread laterally of the burner opening so that the flame approaches thelateral combustion chamber walls.

Cooperating with the specially configured burner throat opening is anozzle assembly that includes a nozzle cap 42 supported centrally oforifice 24 by a fuel supply pipe 44. Pipe 44, in accordance withconventional practice, supplies atomized fuel to nozzle cap 42.Referring to FIGS. 4 and 5, nozzle 42 includes a frustoconical wall 46in which are provided, for example by drilling, a plurality of fuelpassages which have sizes and orientations arranged in respect to thespecific shape ofthe burner throat to form the flame as desired. Morespecifically, the nozzle cap has a pair of upper fluid passages 48a and48b formed through wall 46 at an angle that corresponds with the shapeof the throat at segment 30. Because portion 30' of the throat flaresout at a-substantial angle, fuel passages 48a and 48b are drilled at acorresponding large angle with respect to the central axis of the nozzlestructure. Formation of two holes 48a and 4811, rather than one hole ofan area equal to the sum of areas of the two holes. assures delivery ofa desired quantity of fuel at a sufficiently low kinetic energy level toavoid flame impingement on the wall of the combustion chamber.

Nozzle cap 42 is further provided with lateral fuel orifices 50 and 52which are formed at an angle corresponding to the configuration ofthroat surface portion 32. Because surface portion 32 is flared out by asubstantial amount, the angle at which passages 50 and 52 are formed issubstantial. Accordingly, the lateral spread of the flame as indicatedat 54 in FIG. 2 is substantial so that the flame is shaped tosubstantially fill the combustion chamber. Passages 50 and 52 are formedat a suflicient angle that the fuel issuing therefrom, even though ithas substantial energy, does not impinge on the combustion chamberwalls.

A trinity of lower fuel passages 56a, 56b and 56c is provided in nozzlecap 42. The lower passages are formed the burner throat. In order toreduce the momentum or kinetic energy of the fuel supplied in the lowersector of the furnace, thereby avoiding direct impingement of flame ontofloor 16, the fuel is supplied through three passages 56a, 56b and 560which have a total cross-sectional area sutficient to fire adequatelythe lower portion of the com.- bustion chamber but which have individualcross-sectional areas smaller than the remaining fuel passages.

The nozzle cap 42 depicted in the drawing is somewhat.

simplified for clarity. In actual practice better flame dis; tributionis provided by a cap having more fuel passages therein, suchpassagesbeing formed between those specifically shown and having anglesintermediate the angles at which the passages on either side'of thepassages in question are drilled;

It will be observed-from the specific boiler construction depicted inthe drawing that the distance between front wall '12 and rear wall 14,i.e., the depth of the furnace, is short. Direct impingement of flame onwall 14 is avoided because each fue'l'passag'e' is drilled at-asubstantial angle with respect to the central axis of 'the nozzle. Theangle at which the individual fuel passage is formed depends on thedesired fla'me shape which also dictates the configuration of the throatsurfaceKT-hus, it can be seen that by proper selection 'of nozzlepassage configura tion andthroat shape, the combustion chamber can besubstantially totally filled with flame and direct impingemerit of anypart of th'e'flameonto any part of the combustion chamber wall isavoided. Because the fuel injec tion pattern is substantially dictatedby the configuration of the fuel passages in nozzle 42 and because'theair inflow pattern is determined by the shape of the throat opening, thedesired uniform flame pattern is achieved by use of thepresentinvention. a I

Thus,'it will be seen that the present invention provides an efficieritsingle burner system for efficiently firing boilers that have a largeratio of height and width to depth. The present invention afiords suchburner in a low-cost, maintenance-free unit which can be installed in,both existing and new boiler constructions.

Although one embodiment of the invention has been shown and described,it will be obvious that other adaptations and modifications can be madewithout departing from the true spirit and scopeof the invention.

What is claimed is:

1. In a boiler including a wall having an inner face and outer face, thecombination comprising a throat opening formed in said wall andextending between said outer face and said inner face, said throatopening having a generally circular shape at said outerlwall face anddiverging toward said inner wall face, said throat opening at said innerwall face being symmetrical with respect to a vertical axis and beingasymmetrical relative a horizontal axis, 'said throat opening relativethe ho'riz'ontal axis having a greater upward extent than a downwardextent, a fluid conduit having a terminus approximately coextensive withthe center of said circular throat opening at said outer wall face, afuel nozzle mounted on the terminus for distributing atomized fuel fromsaid conduit within the boiler, said nozzle including a cap having aconvex surface toward the interior of said boiler, said convex surfacedefining a first fuel opening in the upper quadrant thereof and formedto direct atomized fuel into said boiler to the upper region thereof,said convex surface also defining second and third fuel openings in theside quadrants thereof for directing fuel to the central region of theboiler, said second and third fuel openings having a diameter equal tosaid first opening, fourth and fifth fuel openings in said convex capsurface in the lower quadrant thereof for directing fluid in a downwarddirection in said boiler, said fourth and fifth openings having adiameter smaller than said first opening so that fuel issuing from saidfourth and fifth opening'has a shorter trajectory than fuel issuing-fromsaid first, second, andthird fuel openings.

2. In a combustion chamber that includes a front wall having an innerface and an outer face and a side wall extending generally normal ofsaid front wall, the combination which comprises a throat opening formedin said front wall and extending between said outer face and said innerface, said throat opening having a generally circular shape at saidouter wall face and diverging smoothly toward said inner face at whichan inner orifice is defined, said inner orifice having a flattenedportion generally parallel to said sidewall, a single nozzle cap mountedcentrally of the throat opening, and means for delivering fuel to thenozzle cap, said nozzle cap having a plurality of fuel passages thereinwhich are positioned and oriented so as to distribute fuel in saidcombustion chamber, said plurality of fuel passage including at leastone passage- 2,857,148 10/1958 Niemitz 15s 7x 3,285,315 11/1966 Voorheis158-4 x FREDERICK L, MATTEVSON, 111., Primary Examiner. E. G. FAVORS,Assistant Examiner.

